net: reintroduce missing rcu_assign_pointer() calls

commit a9b3cd7f32 (rcu: convert uses of rcu_assign_pointer(x, NULL) to
RCU_INIT_POINTER) did a lot of incorrect changes, since it did a
complete conversion of rcu_assign_pointer(x, y) to RCU_INIT_POINTER(x,
y).

We miss needed barriers, even on x86, when y is not NULL.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Hemminger <shemminger@vyatta.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 3b6dac9..133768e 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -182,7 +182,7 @@
 	     (iter = rtnl_dereference(*tp)) != NULL;
 	     tp = &iter->next) {
 		if (t == iter) {
-			RCU_INIT_POINTER(*tp, t->next);
+			rcu_assign_pointer(*tp, t->next);
 			break;
 		}
 	}
@@ -192,8 +192,8 @@
 {
 	struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 
-	RCU_INIT_POINTER(t->next, rtnl_dereference(*tp));
-	RCU_INIT_POINTER(*tp, t);
+	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
+	rcu_assign_pointer(*tp, t);
 }
 
 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
@@ -393,7 +393,7 @@
 	p->addr = a->addr;
 	p->flags = a->flags;
 	t->prl_count++;
-	RCU_INIT_POINTER(t->prl, p);
+	rcu_assign_pointer(t->prl, p);
 out:
 	return err;
 }
@@ -1177,7 +1177,7 @@
 	if (!dev->tstats)
 		return -ENOMEM;
 	dev_hold(dev);
-	RCU_INIT_POINTER(sitn->tunnels_wc[0], tunnel);
+	rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
 	return 0;
 }